1. Field of the Invention
The present invention relates to a photomultiplier for cascade-multiplying photoelectrons emitted from a photocathode in correspondence with incident light by multilayered dynodes.
2. Related Background Art
Conventionally, photomultipliers have been widely used for various measurements in nuclear medicine and high-energy physics as a y-camera, PET (Positron Emission Tomography), or calorimeter.
A conventional photomultiplier is constituted by a photocathode, provided inside a cylindrical bottomed vacuum container and deposited on the surface of a light receiving plate for receiving incident light, for emitting photoelectrons, focusing electrodes for focusing the orbits of the photoelectrons, and an electron multiplier, including an anode and a dynode unit provided between the photocathode and the anode, for receiving and cascade-multiplying the photoelectrons.